Memory cards such as SIMMs and DIMMs have increasingly more memory and more function being added thereto. Particularly, it has been proposed that signal processing elements such as digital signal processors (DSPs) be provided on board the cards to perform various functions independently of the system memory controller. These DSPs can operate on the memory when it is not being accessed by the system memory controller to perform various tasks.
This provides an inexpensive processor specific to each card to enhance the operation of the memory card. Additionally, as the amount of memory and the functions supplied on each card increase the power requirement for the card with large amounts of memory and more functions, this power requirement can be substantially increased. This is especially critical where the system is battery operated and/or the heat dissipation capability is limited. While the system memory controller generally is programmed to reduce the power level of the memory system, this is generally not a completely satisfactory solution since the memory controller operates on all of the memory cards and generally does not reduce the power state of the memory until the period of non-use amounts to a substantial period of time. Also the system memory controller is not normally programmed to operate on individual portions of memory banks. Thus there is a need for a memory card and system for the memory card to operate in a computer to selectively and expeditiously reduce power to individual banks of memory or portions thereof when the banks of memory or portion thereof are not being accessed by either the system memory controller or the DSP.